Carl --
Thanks for the suggestions.
I had the pedal assembly out of the car when I redid the hydraulics, and
greased all of the pedal bushings in the process. The pedals swing freely,
and return to full stop every time w/o the M/C attached. When the brake
system is in the "hung up" mode, there is noticeable free play in the brake
pedal. When I tap the pedal, the free play disappears as the pedal returns
to the full up position. I don't think there would be any free play if the
pedal linkage was sticking. I'll still check, just to be certain.
FWIW, I noticed this sticking when I was bleeding the system, as well.
Another lister suggested that DOT5 causes the seals to swell. The kit was
new from Moss, so I assume it was the latest seal material, but that
explanation seems to make the most sense. I can imagine that swelling seals
would have a greater effect with the cylinder filled with fluid under
pressure than on the bench.
Dean
> -----Original Message-----
> From: CarlSereda@aol.com [mailto:CarlSereda@aol.com]
> Sent: Friday, July 01, 2005 1:13 PM
> To: triumphs@autox.team.net; Dean Mericas
> Subject: re: RE: Two TR Brake ?'s - Dust & Pressure
>
> Dean,
> I'm beginning to think you are missing the the heavy return
> spring on the pedal arm below the MC platform.. or that there
> is binding with that pedal and nothing to do with the MC..
> Have you tried the pedal on its own to see if there is
> stickiness, catching, or non full return?
> Carl
> '63 TR4 since '74
>
> I don't think I did a very good job of explaining myself. I
> had posted the following in response to the comment below it:
>
> > FWIW, I have had this exact same problem pop up when I recently
> > switched to
> > DOT5 silicone fluif. I've torn down the MC twice, and
> confirmed that
> > it works as I think it should on the bench, and pulled the
> guts out of
> > the residual pressure valve. The problem is reduced, but
> still there.
> >
> > I'm now convinced that this is the result of different fluif
> > properties, as was suggested by another lister. Odd that
> this doesn't
> > show up on all of the web pages discussing the pros and
> cons of DOT5.
>
> The problem I was referring to was not "knock back" but the
> fact that the M/C seems to hang up part way back after
> applying the brakes. The front brakes remain partially
> engaged (drag). Tapping the brake pedal releases it, and it
> springs fully back the last fraction of an inch. Like I
> tried to say, I've disassembled the M/C twice, and the
> piston/spring assembly returns quickly and completely when
> pushed in on the bench. I can't get it to replicate the
> hang-up with it out of the car. The only thing that even
> begins to make sense to me is that somehow with DOT5 fluid
> filling the system, there is some sort of binding between the
> piston and cylinder walls.
>
> Dean Mericas
> Ann Arbor, MI
> 1965 TR4
> 1974 2000 GTV
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